Automatic merge from submit-queue (batch tested with PRs 42900, 43044, 42896, 43308, 43621)
Convert PrefixWriter to an interface
Convert PrefixWriter to an interface to allow other packages to create instances. This is needed for downstream projects such as OpenShift.
cc @sttts @smarterclayton @oulinbao @deads2k @liggitt @kargakis @soltysh @kubernetes/sig-cli-pr-reviews